Ken Pfeuffer, Jason Alexander, Ming Ki Chong, Yanxia Zhang, and Hans Gellersen. 2015. Gaze-Shifting: Direct-Indirect Input with Pen and Touch Modulated by Gaze. In Proceedings of the 28th Annual ACM Symposium on User Interface Software & Technology (UIST '15). Association for Computing Machinery, New York, NY, USA, 373–383. https://doi.org/10.1145/2807442.2807460